TRAF6 and cancer: Interestingly, TRAF6 could also promote the proteolytic cleavage of the polyubiquitylated TGFBR1 by TNF-alpha converting enzyme (TACE) and presenilin-1, which would release the intracellular domain of TGFBR1 for translocation to the nucleus, leading to the transcriptional activation of a specific subset of genes, including Snail and MMP2, ultimately promoting cancer cell invasiveness [32,33,34].